Capsule Set-aside (land temporally removed from agricultural production) features and their regional locations influence steppe-bird species of conservation concern in Catalonia. Aims To identify set-aside features important to the ecology of four ground nesting species, namely Little Bustard Tetrax tetrax , Stone-curlew Burhinus oedicnemus , Greater Short-toed Lark Calandrella brachydactyla and Calandra Lark Melanocorypha calandra . Methods Set-aside fields were surveyed in four regions of Catalonia (northeast of Spain) for the selected species during the 2004 and 2005 breeding seasons. Set-aside habitat descriptors (e.g. size, vegetation structure) were collected. Ordination plots and information theoretic methods were used to assess the relationship between the selected bird species, set-aside features and the regions. Results The region where the set-aside was located had a strong effect on the abundance of the selected species. In addition, vegetation coverage, field shape of set-aside and surrounding natural habitats were critical features, but with contrasting effects on the different species. Conclusion Populations of the selected species of conservation concern could be improved by effective management of set-aside. As selected species responded differently, we recommend that management at local level should take into account the conservation value at a regional level of the protected area for each of the selected species.